67&02camaroSS

I have a 2002 camaro ss m6, pretty much stock except for lid, bellow, and slp y-pipe. i also have the centermount exhaust. i noticed that after half a day of driving the exhuast pipes become black with ****. i talked to some friends and they said that it seems to be running rich. so i borrowed my friends diablo and ran real time diag after the car had been running and set the speed to 55. the short terms were bouncing back and forth between -4 and +4 even with the cruise set. and the long terms were doing the same thing just not every second like the short bands. i stopped got some gas and headed home and long terms went all the way up to 9 and dropped to 7 before i got home. just curious if any of you guys might have any idea what could be causing this issue? i appreciate your help you guys can shed on the subject. if something is up with my car i need to know pretty soon as my warranty will run out in a little while.

thanks

oange ss

iTrader: (50)

stock settings, need to lean out part throttle FT

jimmyblue

iTrader: (11)

My car made soot from new. Now with the cats gutted,
it makes tar instead.

Short term trims bounce around normally. The long trims'
job is to make sure they bounce either side of a zero average,
just as the short trims' job is to ensure the O2s swing about
0.5V evenly.

Positive LTFTs indicate a lean error being covered up by
the trim process. You do not lead part throttle leaned
out if you see positive trims. However, these trims will
stick with you into WOT where (on a stock tune) GM has
over-enriched you to begin with (PE table). Lean in the
base tune, adds to enrichment up top (numerically at
least). The supposition is that your lean error is constant
scaler with airflow. Though things like vacuum leaks are
a class of error where this is untrue. Observe the trend of
the LTFTs with FTC or throttle. More, or less positive with
pedal?

Would your lid happen to house a nice gooey K&N filter?
Anything funny about the MAF? These are the best way to
pick up a lean bias in the base tune.

67&02camaroSS

yeah i have a k&n. yes i have already cleaned the maf with carb cleaner. so in english(i am not compentant on the efi codes and tuning) is this something that the dealership can take car of or am i going to have to pay and get a dyno tune. i am not able to actually use the diablo to tune. i was just using it to check and see how rich if i was running rich.

jimmyblue

iTrader: (11)

I don't think the dealership is going to help you.
You definitely do not want to show up with that
K&N in the air cleaner, that's going to get you
denied any service claim relating to performance
or pinging etc. Also most "dyno tune" places I
think concentrate on the wide-open tune and not
the broader (more labor intensive) street, part-
throttle tuning.

A paper filter and one more can of carb (or electrical)
cleaner would be a cheap enough thing to try.